An efficient synthesis of diethyl coumarin-3-phosphonates
作者:Rajendra K. Singh、Michael D. Rogers
DOI:10.1002/jhet.5570220648
日期:1985.11
A general synthesis of a number of diethylcoumarin-3-phosphonates (3) has been achieved using titanium tetrachloride-pyridine as the condensing agent.
使用四氯化钛-吡啶作为缩合剂已经实现了许多香豆素-3-膦酸二乙酯的一般合成(3)。
SINGH, RAJENDRA, K.;ROGERS, M. D., J. HETEROCYCL. CHEM., 1985, 22, N 6, 1713-1714
作者:SINGH, RAJENDRA, K.、ROGERS, M. D.
DOI:——
日期:——
A Convenient Entry to 3-Methylidenechroman-2-ones and 2-Methylidenedihydrobenzochromen-3-ones
作者:Tomasz Janecki、Jakub Modranka、Anna Albrecht
DOI:10.1055/s-0030-1259046
日期:2010.12
A simple and versatile synthesis of 3-methylidenechroman-2-ones and 2-methylidenedihydrobenzochromen-3-ones has been developed. The reaction of phenols or naphthols with 3-methoxy-2-diethoxyphosphorylacrylate gave intermediate 3-diethoxyphosphorylchromen-2-ones or 2-diethoxyphosphorylbenzo-chromen-3-ones, respectively. These compounds were employed as Michael acceptors in the reaction with Grignard reagents to yield 4-substituted 3-diethoxyphosphorylchroman-2-ones or 1-substituted 2-diethoxyphosphoryldihydrobenzochromen-3-ones. The obtained adducts were next used as Horner-Wadsworth-Emmons reagents for the olefination of formaldehyde to give the final products.
and various substituents at position 4 were synthesized in a three step reaction sequence. Friedel–Crafts alkylation of phenols or naphthols using ethyl 3-methoxy-2-diethoxyphosphorylacrylate in the presence of trifluoromethanesulphonic acid gave 3-diethoxyphosphorylchromen-2-ones. These compounds were employed as Michael acceptors in the reaction with Grignardreagents to give adducts which were finally